JPS6182652A - Time-of-flight type collision dissociation mass spectrometer - Google Patents

Abstract

PURPOSE:To enable a high sensitivity measurement to be conducted by combining first time-of-flight type mass spectrometer including an ionizing chamber and a drift tube with a second time-of-flight type mass spectrometer including a collision chamber and a drift tube. CONSTITUTION:A time-of-flight type collision dissociation mass spectrometer consists of a first time-of-flight type mass spectrometer 1 including an ionizing chamber 2, a lead electrode 4, a drift type 3, and pulse voltage generator means 5, and of a second time-of-flight type spectrometer 11 including an electric field sector 8 being energy selector means, a collision chamber 9 filled with helium, etc., a lead electrode 13, a drift tube 12, and a DC power source 14 for applying voltage between the electrode 13 and the collision chamber 9, and furthermore of an ion detector 15, Accordingly, execution of collision dissociation mass analysis with use of the time-of-flight type mass spectrometer so constructed enables a high sensititvity, high speed measurement without eliminating a range of the numbers of masses to be analyzed.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Industrial Application Field The present invention relates to a time-of-flight collisional dissociation mass spectrometer, and particularly to a flight-time collisional dissociation mass spectrometer that performs mass spectrometry by collisional dissociation using a time-of-flight mass spectrometer and an electric field sector. This invention relates to a time-based collisional dissociation mass spectrometer.

(b) Prior Art When analyzing the molecular weight and molecular structure of an organic compound using mass spectrometry, its parent ion and daughter ion appear in the mass spectrum and provide important molecular structure information. However, if the sample is a mixture or contains impurities, ions from the mixture will also appear in the spectrum, making it difficult to obtain a reliable molecular structure.

Therefore, attempts are being made to select specific ions that appear in the spectrum, collide and dissociate the ions with rare gases such as helium, and obtain molecular structure information from the ions obtained. (This is called collision dissociation mass spectrometry.) In reality, mass spectrometry is performed using two mass spectrometers directly connected as shown in Figure 4 A and B, or a double convergence mass spectrometer. ing. In Figures 4A and B, (a) is the ionization chamber, (b) is the magnetic field sector, (C) is the collision chamber, (
d) is an electric field sector, and (e) is an ion detector.

However, since these IR mass separation devices use a magnetic field sector (b), it is usually necessary to strengthen the magnetic field or lower the ion acceleration voltage in order to handle ions with a high mass number. Therefore, there were disadvantages such as the magnetic field sector (b) becoming very large and ion permeation rate decreasing. Furthermore, since the selection of ions in the magnetic field sector (b) is performed by scanning the magnetic field strength, the total amount of ions cannot be measured, and therefore the amount of the sample becomes large (in the forward direction).

(c) Purpose This invention has been made in view of the above circumstances, and aims to provide a time-of-flight f+i concussion mass spectrometer that has no limitations on the analysis mass number range and is capable of determining θ with high sensitivity. It is something.

(d) Configuration This invention is configured to perform collision dissociation mass spectrometry using a time-of-flight mass spectrometer, and its more detailed configuration includes an ionization chamber for ionizing a sample, and one end facing the ionization chamber. A first flight section for ions, which is equipped with an energy selection means for selecting ions flying therein according to the difference in their momentum and energy when a voltage is applied to the first flight section, and an ionization chamber near the end of the first flight section. A first ion accelerating means for uniformly accelerating ions, which is composed of a first extraction electrode provided and a pulse voltage generating means electrically connected to the ionization chamber, and a first ion accelerating means for uniformly accelerating ions, and A first detector provided at the energy selection means to which the flying ions reach when no voltage is applied; a collision chamber filled with a rare gas and into which flying ions reach when a voltage is applied from the energy selection means; a second flight section for ions provided at one end facing the collision chamber; and a collision chamber and a second flight section. a second ion accelerating means comprising a second extraction electrode provided near the collision chamber side end (a DC power source electrically connected to the collision chamber and the second extraction electrode); and the other of the second flight section. This is a time-of-flight collisional dissociation mass spectrometer characterized by comprising a second ion detector which is provided oppositely at one end of the detector and through which flying ions reach.

(e) Examples Examples of the present invention will be described in detail below with reference to the drawings, but the invention is not limited to the following examples.

Referring to FIG. 1, the configuration of an embodiment using two time-of-flight mass spectrometers of the present invention will be described.

(1) is a time-of-flight mass spectrometer, and the ionization chamber (2)
, a drift tube (3) which is the first flight part, a first extraction electrode (4) provided near the end of the drift tube (3) on the ionization chamber (2) side, and a Pulse voltage generating means (5) connected to one extraction electrode (4)
) and a first ion detector (6) provided opposite to the other end of the drift tube (3). The pulse voltage generating means (5) generates a pulse voltage Vo having a pulse width shorter than the time required for ions of the minimum mass number to be observed to reach the triad tube (3). And the pulse voltage Vo
The ions generated in the ionization chamber (2) are accelerated by constant momentum. And in the above, the first extraction electrode (
4) and the pulse voltage generating means (5) are the first ion accelerating means (7). (8) is an electric field sector which is an energy selection means, which selects specific ions based on the difference in kinetic energy of the ions, and releases the selected ions into a collision chamber (9) filled with a rare gas such as helium. QO) is provided in the gap coaxially with the axis (z) of the time-of-flight mass spectrometer (1), and is provided to allow specific ions to pass through when the electric field sector (8) is not in operation.

This is another time-of-flight mass spectrometer, in which there is a drift tube (12), which is the second flight part for ions, and a drift tube (112), which is located opposite the collision chamber (8).
The collision chamber (the second extraction electrode provided at the end of the 81 side)
13, a collision chamber (8), a second extraction electrode (a DC power supply circle that applies a DC voltage between 13), and a drift tube (provided opposite to the other end of 12). This is a conventionally known device consisting of a second ion detector (151).

Next, the operation will be explained with reference to FIG.

First, uniform momentum acceleration will be explained.

The distance between the ionization chamber (2) and the first extraction electrode 4) is D, the mass of the ions is m, the flight direction of the ions is 2, the amount of charge of the ions is e, and the pulse voltage generator means (5) outputs Assuming that the pulse voltage ■ is (1), the equation of motion of this ion is as follows: where E (t) is the electric field generated by the pulse voltage V(t).

becomes. The velocity V of this ion at time t is then. In other words, since this ion is accelerated by a pulse voltage Vo with a short pulse width Δt due to the time it takes to fly over a distance, the velocity ■ becomes V = −V oΔt (1-3)D. , which shows that the momentum of all ions is equal to eVoΔL/D. Furthermore, the kinetic energy W of uniformly accelerated ions is as follows. This is the kinetic energy W of the accelerated ions
This shows that the difference depends on the mass of the ion. Therefore, among the ions that have exited the drift tube (3), only specific ions that satisfy the following equation pass through the electric field sector (8).

However, Re is the radius of the ion trajectory in the electric field sector (8),
El is the electric field in the electric field sector (8).

The ions selected in the electric field sector (8) collide with the rare gas in a collision chamber 19) arranged subsequently, and are dissociated by collision. If the mass of the daughter ion obtained by collisional dissociation is ml and the mass of its parent ion is mo, then the collisional dissociation is mo
−+ml + (mo −ml), and the kinetic energy of each ion is Wo=−movo2
・・・・・・(1-6) W 1-ml vo2-
(1-7) However, Vo is the speed at which an ion with mass mo is initially accelerated. In other words, the velocity of the ions does not change even after collisional dissociation. Therefore, in a time-of-flight mass spectrometer), equal engineering 4 Lugi acceleration is performed.

At this time, the parent ions and daughter ions fly through the drift tube (12) at the speeds shown in the following equations, and then reach the second ion detector (151).

However, (2) is the acceleration voltage between time-of-flight mass spectrometers.As can be seen from the above equation, the time of flight in the drift tube (I2) depends on the mass, and the time to reach the second ion detector (151) It becomes possible to distinguish between each MW.

Here, the flight time TI of the parent ion to the electric field sector t8)
, the flight time T2 within the electric field sector 18), and the flight time T3 of the daughter ion within the time-of-flight mass spectrometer track, where Ll is the distance from the first extraction electrode 4) to the electric field sector (8). , L2 is the distance from the second extraction electrode 113 to the first ion detector surface, α is the electric field sector (8)
It is the angle between the inlet and outlet of

becomes.

In this time-of-flight collisional dissociation mass spectrometer, 2.
First, without operating the electric field sector (8), the time of flight (T, +T2) is measured using a time-of-flight mass spectrometer]1) to determine the mass of the parent ion. At this time, the parent ions pass through the gap 1101 and reach the first ion detector (6) located at a distance equal to the ion flight time distance within the electric field sector (8). The spectrum S observed at this time is shown in FIG. And daughter Ion 1 is
A voltage is applied to the electric field sector (8) so that the parent ion passes through, and the flight time T3 is measured by the second ion detector (151). In this case, if the parent ion is not completely dissociated, Since the highest mass ion observed by the second ion detector (15), that is, the ion with the longest flight time, is the parent ion, it is unnecessary to measure only the daughter ions mentioned above.At this time, The observed spectrum S2 is shown in FIG.

Next, another embodiment of the present invention will be explained with reference to FIG.

In this embodiment, the drift tube (3) and electric field sector (8) of the above embodiment are not used, but instead the deflection plate 11E+l 1
151 is used. i.e. ionization chamber (2)
The ions are accelerated by a constant momentum in the first ion accelerating means (7) composed of the first extraction electrode 4) and the pulse voltage generating means (5), and then the deflection plate j+6! Specific ions are selected by the electric field formed at f151 and guided to the collision chamber (9). Here, deflection plate f161
f161 and a deflection plate 061 to form an electric field [
A DC power supply (not shown) connected to 151 constitutes energy selection means.

The ions collided and dissociated in the collision chamber (9) are measured by a time-of-flight mass spectrometer 111).

(C) Effects According to the present invention, since a time-of-flight mass spectrometer and an electric field sector are used, there are no restrictions imposed by the magnetic field sector, so time-of-flight collisional dissociation has no limitations on the analysis mass number range. A mass spectrometer is obtained. Furthermore, since there is no need to use a slit, the ion optical system is open and highly sensitive measurement is possible. Furthermore, since it is a total volume measurement that does not require scanning, high-speed measurement is possible and only a small amount of sample is required. This is particularly effective when a large amount of sample cannot be obtained, such as for high molecular weight organic compounds.

[Brief explanation of drawings]

Figure 1 is a schematic diagram of the configuration of an embodiment of this invention, Figure 2 is a spectrum diagram observed in this embodiment, Figure 3 is a schematic diagram of the configuration of another embodiment, and Figures 4A and B are two mass spectrometers directly connected. This is a schematic diagram of the configuration of a conventional example using a dual convergence mass spectrometer. 12)...Ionization chamber, (3)...Drift tube (first flight section), (6)...
First ion detector, (7)...First ion acceleration means, (8)...Electric field sector (energy selection means), (9)
...Collision chamber, 11'2... Drift tube (second flight section), (15)
...Second ion detector, 1171...Second ion acceleration means.

Claims (1)

[Claims] 1. An ionization chamber that ionizes the sample, and an ion chamber with one end facing the ionization chamber and an energy selection means that selects ions flying inside when a voltage is applied based on the difference in their kinetic energies. A first flight section that uniformly accelerates ions, and a pulse voltage generating means that is electrically connected to the ionization chamber and a first extraction electrode provided near the end of the first flight section on the ionization chamber side. a first detector which is provided opposite to the other end of the first flying section and to which the flying ions reach when no voltage is applied to the energy selection means; A collision chamber is provided at an eccentric position in the axial direction of the flight section and is filled with a rare gas, and the collision chamber reaches which the flying ions reach when a voltage is applied from the energy selection means; a second flight section for ions to be flown, a second extraction electrode provided near the collision chamber side end of the second flight section, and a DC power supply electrically connected to the collision chamber and the second extraction electrode. What is claimed is: 1. A time-of-flight collision dissociation mass spectrometer, comprising: a second ion accelerating means; and a second ion detector, which is disposed opposite to the other end of the second flight section and through which flying ions reach.